Femtosecond Dynamics of Excited-State Evolution in     

NH Damrauer  G Cerullo  A Yeh  TR Boussie  CV Shank  JK McCusker 《Science (New York, N.Y.)》1997,275(5296):54-57

Time-resolved absorption spectroscopy on the femtosecond time scale has been used to monitor the earliest events associated with excited-state relaxation in tris-(2,2'-bipyridine)ruthenium(II). The data reveal dynamics associated with the temporal evolution of the Franck-Condon state to the lowest energy excited state of this molecule. The process is essentially complete in approximately 300 femtoseconds after the initial excitation. This result is discussed with regard to reformulating long-held notions about excited-state relaxation, as well as its implication for the importance of non-equilibrium excited-state processes in understanding and designing molecular-based electron transfer, artificial photosynthetic, and photovoltaic assemblies in which compounds of this class are currently playing a key role.  相似文献   

The antiproliferative action of progesterone in uterine epithelium is mediated by Hand2     

Li Q  Kannan A  DeMayo FJ  Lydon JP  Cooke PS  Yamagishi H  Srivastava D  Bagchi MK  Bagchi IC 《Science (New York, N.Y.)》2011,331(6019):912-916

  相似文献   

Erratum to: Organochloride pesticides in California sea lions revisited     

Burney?J?Le BoeufEmail author  John?P?Giesy  Kurunthachalam?Kannan  Natsuko?Kajiwara  Shinsuke?Tanabe  Cathy?Debier 《BMC ecology》2003,3(1):2

There has been an error in the publication of this paper [1]; the title should read: 'Organochlorine pollutants in California sea lions revisited'.  相似文献   

Organochloride pesticides in California sea lions revisited     

Burney J Le Boeuf  John P Giesy  Kurunthachalam Kannan  Natsuko Kajiwara  Shinsuke Tanabe  Cathy Debier 《BMC ecology》2002,2(1):11-8

Background  

Dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that have been banned in most countries, but considerable amounts continue to cycle the ecosphere. Top trophic level predators, like sea birds and marine mammals, bioaccumulate these lipophilic compounds, reflecting their presence in the environment.  相似文献   

Antifeedant activity of Momordica dioica fruit pulp extracts on Spodoptera litura   总被引：3，自引：0，他引：3  

Narasimhan S  Kannan S  Ilango K  Maharajan G 《Fitoterapia》2005,76(7-8):715-717

The hexane extract and ethyl acetate soluble fraction of methanolic extract of the fruit pulp of Momordica dioica exhibited moderate and concentration dependent antifeedant activity against Spodoptera litura.  相似文献   

Influence of paper mill effluent irrigation on the population dynamics of Rhizobium and Azotobacter in sugarcane rhizosphere     

K. Kannan  G. Oblisami  M. Kalidurai 《植物养料与土壤学杂志》1990,153(6):421-424

Application of paper mill effluent to sugarcane grown soils increased the populations of Rhizobium and Azotobacter for a particular time and further increase in the duration of irrigation did not significantly contribute to the increase in populations. Prolonged irrigation of the effluent affected the rhizosphere effect (R:S ratio) of these organisms. Populations of Rhizobium and Azotobacter were more in the rhizosphere of sugarcane and increased with the age of the crop in such soils.  相似文献   

Coplanar polychlorinated biphenyls in aroclor and kanechlor mixtures   总被引：1，自引：0，他引：1  

N Kannan  S Tanabe  T Wakimoto  R Tatsukawa 《Journal of the Association of Official Analytical Chemists》1987,70(3):451-454

Three congeners of coplanar PCBs (non-o-o'-chlorine-substituted polychlorinated biphenyls) were determined in representative commercial PCB preparations. The 3,3',4,4'-tetrachlorobiphenyl was highest in Kanechlor 400 (8500 micrograms/g) and Aroclor 1248 (6060 micrograms/g) followed by Kanechlors 300, 500, and 600 and Aroclors 1242, 1254, and 1260 in that order. The toxic 3,3',4,4',5-pentachlorobiphenyl and 3,3',4,4',5,5'-hexachlorobiphenyl were also detected in those mixtures. The highest concentrations of 3,3',4,4',5-pentachlorobiphenyl were found in Kanechlor 400 (89.3 micrograms/g) and Aroclor 1248 (62.3 micrograms/g) followed by Kanechlors 500, 300, and 600 and Aroclors 1254, 1242, and 1260 in that order. The 3,3',4,4',5,5'-hexachlorobiphenyl was detected in all Kanechlor mixtures, with the highest concentration (1.16 micrograms/g) in Kanechlor 500. However, among Aroclor mixtures, it was detected only in Aroclor 1254 at a concentration of 0.66 micrograms/g. The importance of these toxic constituents in PCB mixtures is worth considering in view of widespread pollution of the environment by PCBs.  相似文献   

Iron and zinc bioavailability in rats fed intrinsically labeled bean and bean-rice infant weaning food products     

Kannan S  Nielsen SS  Rodriguez-Burger AP  Mason AC 《Journal of agricultural and food chemistry》2001,49(10):5063-5069

Beans are the core of the Latin American diet and contain iron and zinc. However, the bioavailability of these trace minerals from beans is low. The objective of this study was to determine if the bioavailability of iron and zinc could be improved with the use of fermentation and germination processing technologies. Black beans native to Costa Rica were grown hydroponically with either radioactive iron or zinc. The influence of fermentation and germination on iron and zinc bioavailability from intrinsically labeled infant weaning food products based on black beans and beans-rice was determined in rats. Mineral bioavailability was determined using whole-body (59)Fe retention for iron, and whole-body (65)Zn retention and incorporation of radiolabel into bone for zinc. Percent absorption of (59)Fe from fermented products ranged between 48.0 and 58.0. Percent absorption of (65)Zn ranged from 57.0 to 64.0. Fermentation did not increase iron bioavailability in rats fed fermented beans without rice. Fermentation of cooked beans significantly increased zinc retention. Germination significantly enhanced iron retention from cooked beans from 46 to 55% and from cooked beans-cooked rice from 34 to 48%. Germination significantly improved zinc absorption and retention from cooked beans without added rice.  相似文献   

Adsorption of Congo Red on Various Activated Carbons. A Comparative Study     

Kannan  Nagarethinam  Meenakshisundaram  Mariappan 《Water, air, and soil pollution》2002,138(1-4):289-305

Studies on the removal of Congo Red (CR) by adsorption on variousactivated carbons [commercial activated carbon (CAC) and indigenously prepared activated carbons(IPACs) from raw materialslike bamboo dust, coconut shell, groundnut shell, rice husk, and straw] have beencarried out with an aim to obtain information on treating effluents from dye/textile industries. The effect of various experimental parameters has been investigated by following batchadsorption technique at 30 ± 1 °C. The percentage removal of dye increased with the decrease in initial concentration, initial pH of the dye solution and particle size of IPACs and increase in contact time and dose of adsorbent. Adsorption data were modelled with the Freundlich and Langmuir adsorption isotherms and first order kinetic equations such asNatarajan and Khalaf, Lagergren, Bhattacharya and Venkbachar equations and intra-particle diffusion model and the models werefound to be applicable. The kinetics of adsorption is observed tobe first order with intra-particle diffusion as one of the rate determining steps. Removal of dye using IPACs is found to be favourable and hence, IPACs could be considered as alternatives to CAC for the treatment of textile effluents, especially for theremoval of dye(s).  相似文献   

Effect of Pulp and Paper Mill Effluent Irrigation on Carbon-di-oxide Evolution in Soils     

K. Kannan  G. Oblisami 《Journal of Agronomy and Crop Science》1990,164(2):116-119

Pulp and paper mill waste water irrigation increased pH, EC, organic carbon and exchangeable sodium content of soils. The increase in organic matter content of soils accelerated microbial activity and hence accelerated substrate decomposition with the release of CO₂. There exhibited a peak followed by a steady-decline in the rate of CO₂ evolution in effluent irrigated soils. The irrigation of pulp and paper mill combined effluent to soils did not affect microbial activity.  相似文献